Simple nanostructures (e.g. nanowires) form complex nanomaterials when connected by single crystalline junctions, offering better mechanical strength and superior charge transport while preserving unique properties associated with the small dimensions. Great research interest has been attracted to study this new class of materials, especially in the field of electronics and energy applications. Synthesis of these materials is challenging, necessitated by the combined features of low dimensionality and high complexity; the former requires growth suppressions whereas the latter demands growth enhancement. To this end, two-dimensional complex nanostructures are exceedingly difficult to grow chemically.